Heretofore, certain kinds of proteins etc. are known to be over-expressed in cancer cells compared with normal parts. Therefore, methods have been proposed that diagnose cancer cells, using a fluorescent probe (agent), by shining light on the expressed protein molecules and that distinguish cancer cells by endoscopic observation of the fluorescence due to the fluorescent probe (for example, see Patent Document 1).
Patent Document 1 discloses an endoscope apparatus for diagnosing cancer cells using one type of fluorescent probe.    Patent Document 1: Japanese Unexamined Patent Application, Publication No. HEI-10-201707